Many spice grinders in common usage are constructed so as to be non-refillable. Such spice grinders comprise a bottle of glass or synthetic plastics, and a two component grinder unit fitted to the bottle.
The first component of the grinder unit is secured to the bottle in such manner that it is non-rotatable and is not removable from the bottle unless an excessive force is applied to prise it off. Damage to the fixed component usually results if it is forced off the bottle.
The second component is rotatable on the first component but cannot be detached from the first component except by exerting excessive force. Again damage normally results.
The components carry co-operating grinding teeth which, on inversion of the bottle and rotation of the second component with respect to the first component, grind the spice which has fallen between the teeth.
One known form of grinder unit has a snap-on cap which is pressed onto the bottle so that a bead on the bottle snaps into an internal groove of the fixed component thereby to prevent removal of the fixed component. Two or more protrusions are provided between the mouth of the bottle and the bead. The fixed component has a circumferential array of protrusions on the inside thereof. The protrusions intermesh as the fixed component is pressed onto the bottle thereby to prevent the fixed component rotating.
Grinder units in which the fixed component screws tightly onto the bottle are not usually of the non-refillable type as the fixed component can be screwed-off the bottle. However, it is also known to provide a bead on the fixed component and groove in the bottle, the bead snapping into the groove as the non-rotatable component reaches its fully screwed on position.
The present invention provides an improved spice grinder of the non-refillable type in which the fixed component is screwed onto the bottle.